use bit fields for class state and field type values. This shrinks the snapshot

use bit fields for class state and field type values. This shrinks the snapshot
size by about 4k
Committed: https://code.google.com/p/dart/source/detail?r=10696

[cshapiro, 2012-08-14 22:05:13]

DBC

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h
File vm/object.h (right):

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h#newcode718
vm/object.h:718: kStateTagBit, kStateTagSize> {}; // NOLINT
This seems to be generating a lint error.  2 spaces should be deposited between
the ; and the //

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/raw_object.h
File vm/raw_object.h (right):

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/raw_object.h#new...
vm/raw_object.h:410: uint8_t state_bits_;  // state, is_const, is_interface.
Any reason not to make this and the related field on line 612 an intptr_t
instead of a uint8_t?  There is no space savings at runtime because of
allocation alignment.

[siva, 2012-08-14 22:40:18]

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h
File vm/object.h (right):

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h#newcode718
vm/object.h:718: kStateTagBit, kStateTagSize> {}; // NOLINT
On 2012/08/14 22:05:13, cshapiro wrote:
> This seems to be generating a lint error.  2 spaces should be deposited
between
> the ; and the //

Done.

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/raw_object.h
File vm/raw_object.h (right):

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/raw_object.h#new...
vm/raw_object.h:410: uint8_t state_bits_;  // state, is_const, is_interface.
True, but it documents the size requirement of these fields more clearly. I want
to avoid the scenario where somebody adds a int8 or int16 field without
realizing that this field only needed to be 8 bits long.


On 2012/08/14 22:05:13, cshapiro wrote:
> Any reason not to make this and the related field on line 612 an intptr_t
> instead of a uint8_t?  There is no space savings at runtime because of
> allocation alignment.

[srdjan, 2012-08-14 22:40:44]

LGTM

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h
File vm/object.h (right):

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h#newcode711
vm/object.h:711: kInterfaceBit,
The partial numeration is confusing. I would numerate them all, especially since
it is not consecutive.

[siva, 2012-08-15 00:17:16]

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h
File vm/object.h (right):

https://chromiumcodereview.appspot.com/10837247/diff/5001/vm/object.h#newcode711
vm/object.h:711: kInterfaceBit,
On 2012/08/14 22:40:44, srdjan wrote:
> The partial numeration is confusing. I would numerate them all, especially
since
> it is not consecutive.

Done.